Imaging lens

ABSTRACT

There is provided an imaging lens with excellent optical characteristics which satisfies demand of a low profile and a low F-number. An imaging lens comprises in order from an object side to an image side, a first lens with positive refractive power, a second lens with positive refractive power, a third lens with negative refractive power, a fourth lens, a fifth lens with positive refractive power, a sixth lens with positive or negative refractive power, and a seventh lens with negative refractive power, wherein said first lens is formed in a meniscus shape having an object-side surface being convex in a paraxial region, said second lens has an image-side surface being concave in a paraxial region, said sixth lens has an image-side surface being concave in a paraxial region, and said seventh lens has an image-side surface being concave in a paraxial region, and predetermined conditional expressions are satisfied.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an imaging lens which forms an image of an object on a solid-state image sensor such as a CCD sensor or a C-MOS sensor used in an imaging device.

Description of the Related Art

In recent years, it becomes common that camera function is mounted in various products, such as information terminal equipment, home appliances, automobiles, and the like. Development of products with the camera function will be made accordingly.

The imaging lens mounted in such equipment is required to be compact and to have high-resolution performance.

As a conventional imaging lens aiming high performance, for example, the imaging lens disclosed in the following Patent Document 1 has been known.

Patent Document 1 (CN109839720A) discloses an imaging lens comprising, in order from an object side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens, and a relationship between a focal length of the first lens and a focal length of the overall optical system, a relationship among a refractive index of the first lens, a focal length of the third lens and a focal length of the fourth lens, and a relationship between a paraxial curvature radius of an object-side surface of the seventh lens and a paraxial curvature radius of an image-side surface of the seventh lens, and a refractive index of the sixth lens satisfy a certain condition.

SUMMARY OF THE INVENTION

However, in lens configurations disclosed in the Patent Document 1, when a low profile and a low F-number are to be realized, it is very difficult to correct aberrations at a peripheral area, and excellent optical performance can not be obtained.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an imaging lens with high resolution which satisfies demand of the low profile and the low F-number in well balance and excellently corrects aberrations.

Regarding terms used in the present invention, “a convex surface (surface being convex)”, “a concave surface (surface being concave)” or “a flat surface (surface being flat)” of lens surfaces implies a shape of the lens surface in a paraxial region (near the optical axis). “Refractive power” implies the refractive power in a paraxial region. “A pole point” implies an off-axial point on an aspheric surface at which a tangential plane intersects the optical axis perpendicularly. “A total track length” is defined as a distance along the optical axis from an object-side surface of an optical element located closest to the object to an image plane. “The total track length” and “a back focus” are distances obtained when thickness of an IR cut filter or a cover glass which may be arranged between the imaging lens and the image plane is converted into an air-converted distance.

An imaging lens according to the present invention comprises, in order from an object side to an image side, a first lens with positive refractive power, a second lens with positive refractive power, a third lens with negative refractive power, a fourth lens, a fifth lens with positive refractive power, a sixth lens with positive or negative refractive power, and a seventh lens with negative refractive power, wherein said first lens is formed in a meniscus shape having an object-side surface being convex in a paraxial region, said second lens has an image-side surface being concave in a paraxial region, said sixth lens has an image-side surface being concave in a paraxial region, and said seventh lens has an image-side surface being concave in a paraxial region.

The first lens is formed in a meniscus shape having the object-side surface being convex in the paraxial region, and spherical aberration, coma aberration, astigmatism, field curvature, and distortion are suppressed.

The second lens has the positive refractive power, and the spherical aberration is properly corrected. Furthermore, the second lens has the image-side surface being concave in the paraxial region, and the coma aberration, the astigmatism, the field curvature, and the distortion are properly corrected.

The third lens has the negative refractive power, and chromatic aberration, the coma aberration, the astigmatism, and the distortion are properly corrected.

The fourth lens has at least one aspheric surface, and the astigmatism, the field curvature, and the distortion are properly corrected.

The fifth lens has the positive refractive power, and the astigmatism, the field curvature, and the distortion are properly corrected.

The sixth lens has at least one aspheric surface, and the astigmatism, the field curvature, and the distortion are properly corrected. Furthermore, the sixth lens has the image-side surface being concave in the paraxial region, and the astigmatism, the field curvature, and the distortion can be more properly corrected.

The seventh lens has the negative refractive power and at least one aspheric surface, and the chromatic aberration, the astigmatism, the field curvature, and the distortion are properly corrected. Furthermore, the seventh lens has the image-side surface being concave in the paraxial region, and a low profile is maintained and a back focus are secured.

According to the imaging lens having the above-described configuration, it is preferable that an object-side surface of the third lens is convex in the paraxial region.

When the object-side surface of the third lens is convex in the paraxial region, the coma aberration, the astigmatism, and the distortion can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that an object-side surface of the sixth lens is formed as an aspheric surface having at least one pole point in a position off the optical axis.

When the object-side surface of the sixth lens is formed as an aspheric surface having at least one pole point in a position off the optical axis, the astigmatism, the field curvature, and the distortion can be more properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the image-side surface of the sixth lens is formed as the aspheric surface having at least one pole point in a position off the optical axis.

When the image-side surface of the sixth lens is formed as the aspheric surface having at least one pole point in a position off the optical axis, the astigmatism, the field curvature, and the distortion can be more properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the image-side surface of the seventh lens is formed as the aspheric surface having at least one pole point in a position off the optical axis.

When the image-side surface of the seventh lens is formed as the aspheric surface having at least one pole point in a position off the optical axis, the astigmatism, the field curvature, and the distortion can be more properly corrected, and a light ray incident angle to an image sensor can be appropriately controlled.

The imaging lens according to the present invention, due to the above-mentioned configuration, achieves a low profile which a ratio of a total track length to a diagonal length of an effective image area of the image sensor is 0.7 or less and a low F number of 2.0 or less.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (1) is satisfied:

3.85<|r13/r14|  (1)

where

r13: a paraxial curvature radius of an object-side surface of the seventh lens, and

r14: a paraxial curvature radius of an image-side surface of the seventh lens.

The conditional expression (1) defines an appropriate range of a relationship between the paraxial curvature radius of the object-side surface of the seventh lens and the paraxial curvature radius of the image-side surface of the seventh lens. By satisfying the conditional expression (1), the astigmatism, the field curvature and the distortion can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (2) is satisfied:

13.00<vd6<34.00  (2)

where

vd6: an abbe number at d-ray of the sixth lens.

The conditional expression (2) defines an appropriate range of the abbe number at d-ray of the sixth lens. By satisfying the conditional expression (2), the chromatic aberration can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (3) is satisfied:

−3.50<f2/f7<−0.50  (3)

where

f2: a focal length of the second lens, and

f7: a focal length of the seventh lens.

The conditional expression (3) defines an appropriate range of a relationship between the focal length of the second lens and the focal length of the seventh lens. By satisfying the conditional expression (3), the chromatic aberration, the spherical aberration, the coma aberration, the astigmatism, the field curvature, and the distortion can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (4) is satisfied:

0.00<f1/|f6|<0.30  (4)

where

f1: a focal length of the first lens, and

f6: a focal length of the sixth lens.

The conditional expression (4) defines an appropriate range of a relationship between the focal length of the first lens and the focal length of the sixth lens. By satisfying the conditional expression (4), the profile can be reduced, and the spherical aberration, the coma aberration, the astigmatism, the field curvature, and the distortion can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (5) is satisfied:

0.02<r12/|r13|<0.35  (5)

where

r12: a paraxial curvature radius of an image-side surface of the sixth lens, and

r13: a paraxial curvature radius of an object-side surface of the seventh lens.

The conditional expression (5) defines an appropriate range of a relationship between the paraxial curvature radius of the image-side surface of the sixth lens and the paraxial curvature radius of the object-side surface of the seventh lens. By satisfying the conditional expression (5), the astigmatism, the field curvature and the distortion can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (6) is satisfied:

0.15<D4/T4<1.05  (6)

where

D4: a thickness along the optical axis of the fourth lens, and

T4: a distance along the optical axis from an image-side surface of the fourth lens to an object-side surface of the fifth lens.

The conditional expression (6) defines an appropriate range of a relationship between the thickness along the optical axis of the fourth lens and the distance along the optical axis from the image-side surface of the fourth lens to the object-side surface of the fifth lens. By satisfying the conditional expression (6), reduction in the profile can be achieved, and the astigmatism and the distortion can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (7) is satisfied:

13.00<vd4<34.00  (7)

where

vd4: an abbe number at d-ray of the fourth lens.

The conditional expression (7) defines an appropriate range of the abbe number at d-ray of the fourth lens. By satisfying the conditional expression (7), the chromatic aberration can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (8) is satisfied:

0.03<T2/T4<0.15  (8)

where

T2: a distance along the optical axis from an image-side surface of the second lens to an object-side surface of the third lens, and

T4: a distance along the optical axis from an image-side surface of the fourth lens to an object-side surface of the fifth lens.

The conditional expression (8) defines an appropriate range of a relationship between the distance along the optical axis from the image-side surface of the second lens to the object-side surface of the third lens, and the distance along the optical axis from the image-side surface of the fourth lens to the object-side surface of the fifth lens. By satisfying the conditional expression (8), reduction in the profile can be achieved, and the astigmatism and the distortion can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (9) is satisfied:

0.60<f1/f<2.30  (9)

where

f1: a focal length of the first lens, and

f: a focal length of the overall optical system of the imaging lens.

The conditional expression (9) defines an appropriate range of the focal length of the first lens. By satisfying the conditional expression (9), reduction in the profile can be achieved, and the spherical aberration, the coma aberration, the astigmatism, the field curvature, and the distortion can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (10) is satisfied:

4.50<|f6|/f  (10)

where

f6: a focal length of the sixth lens, and

f: a focal length of the overall optical system of the imaging lens.

The conditional expression (10) defines an appropriate range of the focal length of the sixth lens. By satisfying the conditional expression (10), the astigmatism, the field curvature, and the distortion can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (11) is satisfied:

0.50<f3/f7<4.50  (11)

where

f3: a focal length of the third lens, and

f7: a focal length of the seventh lens.

The conditional expression (11) defines an appropriate range of a relationship between the focal length of the third lens and the focal length of the seventh lens. By satisfying the conditional expression (11), the chromatic aberration, the coma aberration, the astigmatism, the field curvature, and the distortion can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (12) is satisfied:

2.40<r4/f<230.00  (12)

where

r4: a paraxial curvature radius of an image-side surface of the second lens, and

f: a focal length of the overall optical system of the imaging lens.

The conditional expression (12) defines an appropriate range of the paraxial curvature radius of the image-side surface of the second lens. By satisfying the conditional expression (12), the spherical aberration, the coma aberration, the astigmatism, the field curvature, and the distortion can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (13) is satisfied:

0.25<r11/f<1.00  (13)

where

r11: a paraxial curvature radius of an object-side surface of the sixth lens, and

f: a focal length of the overall optical system of the imaging lens.

The conditional expression (13) defines an appropriate range of the paraxial curvature radius of the object-side surface of the sixth lens. By satisfying the conditional expression (13), the astigmatism, the field curvature, and the distortion can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (14) is satisfied:

0.25<r12/f<1.00  (14)

where

r12: a paraxial curvature radius of an image-side surface of the sixth lens, and

f: a focal length of the overall optical system of the imaging lens.

The conditional expression (14) defines an appropriate range of the paraxial curvature radius of the image-side surface of the sixth lens. By satisfying the conditional expression (14), the astigmatism, the field curvature, and the distortion can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (15) is satisfied:

1.75<|r13|/f<100.00  (15)

where

r13: a paraxial curvature radius of an object-side surface of the seventh lens, and

f: a focal length of the overall optical system of the imaging lens.

The conditional expression (15) defines an appropriate range of the paraxial curvature radius of the object-side surface of the seventh lens. By satisfying the conditional expression (15), the astigmatism, the field curvature, and the distortion can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (16) is satisfied:

15.50<r2/T1<42.50  (16)

where

r2: a paraxial curvature radius of an image-side surface of the first lens, and

T1: a distance along the optical axis from an image-side surface of the first lens to an object-side surface of the second lens.

The conditional expression (16) defines an appropriate range of a relationship between the paraxial curvature radius of the image-side surface of the first lens and the distance along the optical axis from the image-side surface of the first lens to the object-side surface of the second lens. By satisfying the conditional expression (16), reduction in the profile can be achieved, and the spherical aberration, the astigmatism, and the distortion can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (17) is satisfied:

15.50<r3/T1<48.50  (17)

where

r3: a paraxial curvature radius of an object-side surface of the second lens, and

T1: a distance along the optical axis from an image-side surface of the first lens to an object-side surface of the second lens.

The conditional expression (17) defines an appropriate range of a relationship between the paraxial curvature radius of the object-side surface of the second lens and the distance along the optical axis from the image-side surface of the first lens to the object-side surface of the second lens. By satisfying the conditional expression (17), reduction in the profile can be achieved, and the spherical aberration, the coma aberration, the astigmatism, the field curvature, and the distortion can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (18) is satisfied:

5.00<|r9|/T4<43.00  (18)

where

r9: a paraxial curvature radius of an object-side surface of the fourth lens, and

T4: a distance along the optical axis from an image-side surface of the fourth lens to an object-side surface of the fifth lens.

The conditional expression (18) defines an appropriate range of a relationship between the paraxial curvature radius of the object-side surface of the fourth lens and the distance along the optical axis from the image-side surface of the fourth lens to the object-side surface of the fifth lens. By satisfying the conditional expression (18), reduction in the profile can be achieved, and the astigmatism, the field curvature, and the distortion can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (19) is satisfied:

2.50<r12/T6<11.50  (19)

where

r12: a paraxial curvature radius of an image-side surface of the sixth lens, and

T6: a distance along the optical axis from an image-side surface of the sixth lens to an object-side surface of the seventh lens.

The conditional expression (19) defines an appropriate range of a relationship between the paraxial curvature radius of the image-side surface of the sixth lens and the distance along the optical axis from the image-side surface of the sixth lens to the object-side surface of the seventh lens. By satisfying the conditional expression (19), reduction in the profile can be achieved, and the astigmatism, the field curvature, and the distortion can be properly corrected.

According to the imaging lens having the above-described configuration, it is preferable that the following conditional expression (20) is satisfied:

25.00<|r13|/D7  (20)

where

r13: a paraxial curvature radius of an object-side surface of the seventh lens, and

D7: a thickness along the optical axis of the seventh lens.

The conditional expression (20) defines an appropriate range of a relationship between the paraxial curvature radius of the object-side surface of the seventh lens and the thickness along the optical axis of the seventh lens. By satisfying the conditional expression (20), reduction in the profile can be achieved, and the astigmatism, the field curvature, and the distortion can be properly corrected.

Effect of Invention

According to the present invention, there can be provided an imaging lens with high resolution which satisfies demand of the low profile and the low F-number in well balance, and properly corrects aberrations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing an imaging lens in Example 1 according to the present invention.

FIG. 2 shows spherical aberration, astigmatism, and distortion of the imaging lens in Example 1 according to the present invention.

FIG. 3 is a schematic view showing an imaging lens in Example 2 according to the present invention.

FIG. 4 shows spherical aberration, astigmatism, and distortion of the imaging lens in Example 2 according to the present invention.

FIG. 5 is a schematic view showing an imaging lens in Example 3 according to the present invention.

FIG. 6 shows spherical aberration, astigmatism, and distortion of the imaging lens in Example 3 according to the present invention.

FIG. 7 is a schematic view showing an imaging lens in Example 4 according to the present invention.

FIG. 8 shows spherical aberration, astigmatism, and distortion of the imaging lens in Example 4 according to the present invention.

FIG. 9 is a schematic view showing an imaging lens in Example 5 according to the present invention.

FIG. 10 shows spherical aberration, astigmatism, and distortion of the imaging lens in Example 5 according to the present invention.

FIG. 11 is a schematic view showing an imaging lens in Example 6 according to the present invention.

FIG. 12 shows spherical aberration, astigmatism, and distortion of the imaging lens in Example 6 according to the present invention.

FIG. 13 is a schematic view showing an imaging lens in Example 7 according to the present invention.

FIG. 14 shows spherical aberration, astigmatism, and distortion of the imaging lens in Example 7 according to the present invention.

FIG. 15 is a schematic view showing an imaging lens in Example 8 according to the present invention.

FIG. 16 shows spherical aberration, astigmatism, and distortion of the imaging lens in Example 8 according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, the preferred embodiment of the present invention will be described in detail referring to the accompanying drawings.

FIGS. 1, 3, 5, 7, 9, 11, 13 and 15 are schematic views of the imaging lenses in Examples 1 to 8 according to the embodiments of the present invention, respectively.

The imaging lens according to the present invention comprises, in order from an object side to an image side, a first lens L1 with positive refractive power, a second lens L2 with positive refractive power, a third lens L3 with negative refractive power, a fourth lens L4, a fifth lens L5 with positive refractive power, a sixth lens L6 with positive or negative refractive power, and a seventh lens L7 with negative refractive power, wherein said first lens L1 is formed in a meniscus shape having an object-side surface being convex in a paraxial region, said second lens L2 has an image-side surface being concave in a paraxial region, said sixth lens L6 has an image-side surface being concave in a paraxial region, and said seventh lens L7 has an image-side surface being concave in a paraxial region.

A filter IR such as an IR cut filter or a cover glass is arranged between the seventh lens L7 and an image plane IMG (namely, the image plane of an image sensor). The filter IR is omissible.

By arranging an aperture stop ST on the object side of the first lens L1, correction of aberrations and control of an incident angle of the light ray of high image height to an image sensor become facilitated.

The first lens L1 has the positive refractive power and is formed in a meniscus shape having the object-side surface being convex and an image-side surface being concave in a paraxial region (near the optical axis X). Therefore, spherical aberration, coma aberration, astigmatism, field curvature, and distortion are suppressed.

The second lens L2 has the positive refractive power and is formed in a meniscus shape having an object-side surface being convex and the image-side surface being concave in a paraxial region (near the optical axis X). Therefore, the spherical aberration, the coma aberration, the astigmatism, the field curvature, and the distortion are properly corrected.

The third lens L3 has the negative refractive power and is formed in a meniscus shape having an object-side surface being convex and an image-side surface being concave in a paraxial region (near the optical axis X). Therefore, chromatic aberration, the coma aberration, the astigmatism, and the distortion are properly corrected.

The fourth lens L4 substantially has no refractive power, and is formed in a shape having an object-side surface and an image-side surface which are flat in a paraxial region (near the optical axis X). Therefore, the astigmatism, the field curvature, and the distortion are properly corrected by aspheric surfaces on both sides without affecting a focal length of the overall optical system of the imaging lens.

Refractive power of the fourth lens L4 may be small positive refractive power which has a little influence on the focal length of the overall optical system of the imaging lens as in Example 7 shown in FIG. 13. In this case, the fourth lens is favorable for reduction in the profile. Furthermore, the refractive power of the fourth lens L4 may be small negative refractive power which has a little influence on the focal length of the overall optical system of the imaging lens as in Example 8 shown in FIG. 15. In this case, the fourth lens is favorable for correction of the chromatic aberration.

The fourth lens L4 may be formed in a meniscus shape having an object-side surface being convex and an image-side surface being concave in the paraxial region (near the optical axis X) as in Examples 7 and 8 shown in FIGS. 13 and 15. In this case, the fourth lens is favorable for correction of the astigmatism and the distortion.

The fifth lens L5 has the positive refractive power and is formed in a biconvex shape having an object-side surface being convex and an image-side surface being convex in a paraxial region (near the optical axis X). Therefore, reduction in the profile is achieved by positive refractive powers on the both sides, and the astigmatism, the field curvature, and the distortion are properly corrected.

The fifth lens L5 may be formed in a meniscus shape having the object-side surface being convex and the image-side surface being concave in a paraxial region (near the optical axis X) as in Example 2 shown in FIG. 3. In this case, the fifth lens is favorable for correction of the astigmatism and the distortion. Furthermore, the fifth lens L5 may be formed in a meniscus shape having the object-side surface being concave and the image-side surface being convex in the paraxial region as in Examples 3, 4, and 5 shown in FIGS. 5, 7, and 9. In this case, the fifth lens appropriately controls a light ray incident angle to the fifth lens L5 and is favorable for correcting the astigmatism, the field curvature, and the distortion.

The sixth lens L6 has the positive refractive power and is formed in a meniscus shape having an object-side surface being convex and the image-side surface being concave in a paraxial region (near the optical axis X). Therefore, the astigmatism, the field curvature, and the distortion are properly corrected.

Refractive power of the sixth lens L6 may be negative refractive power as in Examples 3, 4, and 5 shown in FIGS. 5, 7, and 9. In this case, the sixth lens is favorable for correction of the chromatic aberration.

The object-side surface of the sixth lens L6 is formed as an aspheric surface having at least one pole point in a position off the optical axis X. Therefore, the astigmatism, the field curvature, and the distortion are more properly corrected.

The image-side surface of the sixth lens L6 is formed as an aspheric surface having at least one pole point in a position off the optical axis X. Therefore, the astigmatism, the field curvature, and the distortion are more properly corrected.

The seventh lens L7 has the negative refractive power and is formed in a meniscus shape having an object-side surface being convex and the image-side surface being concave in a paraxial region. Therefore, the chromatic aberration, the astigmatism, the field curvature, and the distortion are properly corrected. Furthermore, providing the image-side surface being concave in the paraxial region, a back focus is secured while maintaining the low profile.

The image-side surface of the seventh lens L7 is formed as an aspheric surface having at least one pole point in a position off the optical axis X. Therefore, the astigmatism, the field curvature, and the distortion are more properly corrected.

Regarding the imaging lens according to the present embodiments, it is preferable that all lenses of the first lens L1 to the seventh lens L7 are single lenses. Configuration only with the single lenses can frequently use the aspheric surfaces. In the present embodiments, all lens surfaces are formed as appropriate aspheric surfaces, and the aberrations are properly corrected. Furthermore, in comparison with the case in which a cemented lens is used, workload is reduced, and manufacturing in low cost becomes possible.

It is preferable that all of lens-surfaces are formed as aspheric surfaces, however, spherical surfaces easy to be manufactured may be adopted in accordance with required performance.

The imaging lens according to the present embodiments shows preferable effect by satisfying the following conditional expressions (1) to (20).

3.85<|r13/r14|  (1)

13.00<vd6<34.00  (2)

−3.50<f2/f7<−0.50  (3)

0.00<f1/|f6|<0.30  (4)

0.02<r12/|r13|<0.35  (5)

0.15<D4/T4<1.05  (6)

13.00<vd4<34.00  (7)

0.03<T2/T4<0.15  (8)

0.60<f1/f<2.30  (9)

4.50<|f6|/f  (10)

0.50<f3/f7<4.50  (11)

2.40<r4/f<230.00  (12)

0.25<r11/f<1.00  (13)

0.25<r12/f<1.00  (14)

1.75<|r13|/f<100.00  (15)

15.50<r2/T1<42.50  (16)

15.50<r3/T1<48.50  (17)

5.00<|r9|/T4<43.00  (18)

2.50<r12/T6<11.50  (19)

25.00<|r13|/D7  (20)

where

vd4: an abbe number at d-ray of the fourth lens L4,

vd6: an abbe number at d-ray of the sixth lens L6,

D4: a thickness along the optical axis X of the fourth lens L4,

D7: a thickness along the optical axis X of the seventh lens L7,

T1: a distance along the optical axis X from an image-side surface of the first lens L1 to an object-side surface of the second lens L2,

T2: a distance along the optical axis X from an image-side surface of the second lens L2 to an object-side surface of the third lens L3,

T4: a distance along the optical axis X from an image-side surface of the fourth lens L4 to an object-side surface of the fifth lens L5,

T6: a distance along the optical axis X from an image-side surface of the sixth lens L6 to an object-side surface of the seventh lens L7,

f: a focal length of the overall optical system of the imaging lens,

f1: a focal length of the first lens L1,

f2: a focal length of the second lens L2,

f3: a focal length of the third lens L3,

f6: a focal length of the sixth lens L6,

f7: a focal length of the seventh lens L7,

r2: a paraxial curvature radius of an image-side surface of the first lens L1,

r3: a paraxial curvature radius of an object-side surface of the second lens L2,

r4: a paraxial curvature radius of an image-side surface of the second lens L2,

r9: a paraxial curvature radius of an object-side surface of the fourth lens L4,

r11: a paraxial curvature radius of an object-side surface of the sixth lens L6,

r12: a paraxial curvature radius of an image-side surface of the sixth lens L6,

r13: a paraxial curvature radius of an object-side surface of the seventh lens L7, and

r14: a paraxial curvature radius of an image-side surface of the seventh lens L7.

It is not necessary to satisfy the above all conditional expressions, and by satisfying the conditional expression individually, operational advantage corresponding to each conditional expression can be obtained.

The imaging lens according to the present embodiments shows further preferable effect by satisfying the following conditional expressions (1a) to (20a).

4.70<|r13/r14|<45.00  (1a)

16.00<vd6<30.00  (2a)

−2.75<f2/f7<−0.90  (3a)

0.00<f1/|f6|<0.25  (4a)

0.04<r12/|r13|<0.25  (5a)

0.40<D4/T4<0.95  (6a)

16.00<vd4<64.00  (7a)

0.05<T2/T4<0.10  (8a)

0.95<f1/f<2.00  (9a)

6.25<|f6|/f<2000.00  (10a)

1.20<f3/f7<3.50  (11a)

2.85<r4/f<190.00  (12a)

0.40<r11/f<0.85  (13a)

0.40<r12/f<0.85  (14a)

2.40<|r13|/f<25.00  (15a)

17.50<r2/T1<32.00  (16a)

17.50<r3/T1<40.00  (17a)

8.50<|r9|/T4<37.00  (18a)

3.80<r12/T6<9.50  (19a)

30.00<|r13|/D7<200.00  (20a)

The signs in the above conditional expressions have the same meanings as those in the paragraph before the preceding paragraph.

In this embodiment, the aspheric shapes of the aspheric surfaces of the lens are expressed by Equation 1, where Z denotes an axis in the optical axis direction, H denotes a height perpendicular to the optical axis, R denotes a paraxial curvature radius, k denotes a conic constant, and A4, A6, A8, A10, A12, A14, A16, A18 and A20 denote aspheric surface coefficients.

$\begin{matrix} {Z = {\frac{\frac{H^{2}}{R}}{1 + \sqrt{1 - {\left( {k + 1} \right)\frac{H^{2}}{R^{2}}}}} + {A_{4}H^{4}} + {A_{6}H^{6}} + {A_{8}H^{8}} + {A_{10}H^{10}} + {A_{12}H^{12}} + {A_{14}H^{14}} + {A_{16}H^{16}} + {A_{18}H^{18}} + {A_{20}H^{20}}}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack \end{matrix}$

Next, examples of the imaging lens according to this embodiment will be explained. In each example, f denotes a focal length of the overall optical system of the imaging lens, Fno denotes a F-number, w denotes a half field of view, ih denotes a maximum image height, and TTL denotes a total track length. Additionally, i denotes a surface number counted from the object side, r denotes a paraxial curvature radius, d denotes a distance of lenses along the optical axis (surface distance), Nd denotes a refractive index at d-ray (reference wavelength), and vd denotes an abbe number at d-ray. As for aspheric surfaces, an asterisk (*) is added after surface number i.

Example 1

The basic lens data is shown below in Table 1.

TABLE 1 Example 1 Unit mm f = 6.69 Fno = 1.95 ω(°) = 42.5 h = 6.25 TTL = 7.43 Surface Data i r d Nd νd (Object) Infinity Infinity  1 (Stop) Infinity −0.4469  2* 2.6058 0.5426 1.535 55.69 (νd1)  3* 4.4454 0.1976  4* 4.2354 0.6890 1.535 55.69 (νd2)  5* 24.9370 0.0500  6* 15.0229 0.3000 1.671 19.24 (νd3)  7* 5.7129 0.4853  8* Infinity 0.4239 1.671 19.24 (νd4)  9* Infinity 0.6575 10* 18.5698 0.5200 1.535 55.69 (νd5) 11* −66.4145 0.5419 12* 3.8326 0.5500 1.671 19.24 (νd6) 13* 3.7650 0.7230 14* 35.6586 0.6892 1.535 55.69 (νd7) 15* 3.4689 0.4000 16 Infinity 0.2100 1.517 64.20 17 Infinity 0.5201 Image Plane Infinity Constituent Lens Data TTL to diagonal length Lens Start Surface Focal Length of effective image area 1 2 10.677 0.59 2 4 9.430 3 6 −13.924 4 8 Infinity 5 10 27.193 6 12 140.435 7 14 −7.239 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5th Surface 6th Surface 7th Surface 8th Surface k −1.797180E+00 −1.754387E+01 −1.376783E+00 0.000000E+00  0.000000E+00  8.217727E+00 −2.011736E+01 A4 −1.477304E−02  2.979555E−03 −3.350337E−02 −8.315653E−02  −5.763141E−02 −2.726318E−02 −1.271261E−02 A6  6.310304E−02  8.616503E−03  9.091011E−02 1.174470E−01  8.969886E−02  1.001072E−01 −9.348891E−02 A8 −1.193991E−01 −3.038989E−02 −1.881465E−01 −9.734332E−02  −3.496699E−02 −1.711838E−01  2.234841E−01 A10  1.325188E−01  4.432910E−02  2.509227E−01 2.647400E−02 −5.726829E−02  1.901255E−01 −3.150695E−01 A12 −9.226317E−02 −3.686253E−02 −2.086369E−01 2.988617E−02  9.638554E−02 −1.327241E−01  2.791395E−01 A14  4.028446E−02  1.861250E−02  1.096955E−01 −3.618064E−02  −6.913410E−02  5.368929E−02 −1.563687E−01 A16 −1.069355E−02 −5.518080E−03 −3.539098E−02 1.759073E−02  2.783676E−02 −1.000796E−02  5.356596E−02 A18  1.576802E−03  8.719524E−04  6.408408E−03 −4.208714E−03  −6.098680E−03 −7.149316E−05 −1.018471E−02 A20 −9.921308E−05 −5.668850E−05 −5.012896E−04 4.006308E−04  5.634313E−04  2.090606E−04  8.186416E−04 9th Surface 10th Surface 11th Surface 12th Surface 13th Surface 14th Surface 15th Surface k −3.957558E+00 4.949817E+01 −1.571850E+01  0.000000E+00  0.000000E+00  4.493056E+01 −1.679157E+01 A4 −3.127025E−02 2.280018E−02  2.370249E−02 −1.148511E−02 −1.349904E−02 −7.439322E−02 −3.321396E−02 A6 −9.158736E−03 −4.379800E−02  −3.769018E−02 −1.927176E−02 −1.580650E−02  1.311740E−02  2.053146E−03 A8  2.383111E−02 3.638715E−02  2.726800E−02  7.417869E−03  6.639494E−03 −8.714856E−04  8.990798E−04 A10 −3.267458E−02 −2.032879E−02  −1.219693E−02 −1.438670E−03 −1.616180E−03 −1.079155E−05 −2.235566E−04 A12  2.725614E−02 7.046699E−03  3.328120E−03  1.143140E−04  2.546766E−04  5.910517E−06  2.393066E−05 A14 −1.379152E−02 −1.517496E−03  −5.557174E−04  3.415916E−06 −2.590541E−05 −4.403866E−07 −1.440038E−06 A16  4.127497E−03 1.976030E−04  5.563538E−05 −1.167047E−06  1.625391E−06  1.636313E−08  5.040712E−08 A18 −6.631858E−04 −1.419008E−05  −3.076089E−06  6.814305E−08 −5.655775E−08 −3.175609E−10 −9.588362E−02 A20  4.366859E−05 4.301586E−07  7.236326E−08 −1.251775E−09  8.251340E−10  2.571453E−12  7.667720E−12

The imaging lens in Example 1 achieves a ratio of a total track length to a diagonal length of an effective image area of the image sensor of 0.59, and a F number of 1.95. As shown in Table 9, the imaging lens in Example 1 satisfies the conditional expressions (1) to (20).

FIG. 2 shows spherical aberration (mm), astigmatism (mm), and distortion (%) of the imaging lens in Example 1. The spherical aberration diagram shows the amount of aberration at each wavelength of F-ray (486 nm), d-ray (588 nm), and C-ray (656 nm). The astigmatism diagram shows the amount of aberration at d-ray on a sagittal image surface S (solid line) and the amount of aberration at d-ray on tangential image surface T (broken line), respectively (same as FIGS. 4, 6, 8, 10, 12, 14 and 16). As shown in FIG. 2, each aberration is corrected excellently.

Example 2

The basic lens data is shown below in Table 2.

TABLE 2 Example 2 Unit mm f = 6.70 Fno = 1.90 ω(°) = 42.6 h = 6.25 TTL = 7.43 Surface Data i r d Nd νd (Object) Infinity Infinity  1 (Stop) Infinity −0.4250  2* 2.6475 0.6524 1.553 71.68 (νd1)  3* 5.6589 0.2277  4* 7.3069 0.5965 1.544 55.93 (νd2)  5* 37.9928 0.0403  6* 9.7336 0.3439 1.661 20.37 (νd3)  7* 5.7265 0.4389  8* Infinity 0.4375 1.639 23.52 (νd4)  9* Infinity 0.6835 10* 14.1500 0.5252 1.535 55.69 (νd5) 11* 90.6494 0.4380 12* 3.9108 0.5037 1.614 25.59 (νd6) 13* 3.8662 0.7155 14* 82.3169 0.7500 1.535 55.69 (νd7) 15* 3.8164 0.1814 16 Infinity 0.2100 1.517 64.20 17 Infinity 0.7558 Image Plane Infinity Constituent Lens Data TTL to diagonal length Lens Start Surface Focal Length of effective image area 1 2 8.347 0.59 2 4 16.508 3 6 −21.797 4 8 Infinity 5 10 31.277 6 12 167.459 7 14 −7.508 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5th Surface 6th Surface 7th Surface 8th Surface k −2.094722E+00  0.000000E+00  2.515211E+00  0.000000E+00 0.000000E+00 0.000000E+00  0.000000E+00 A4  5.979414E−03 −1.767798E−02 −1.640186E−02 −7.284608E−02 −6.264000E−02  −6.133180E−03  −3.273740E−02 A6  4.590726E−03  1.499652E−02  2.327911E−02  1.009840E−01 1.067250E−01 1.173134E−02 −1.463808E−02 A8 −1.639637E−02 −3.361488E−02 −3.707371E−02 −7.299058E−02 −9.307705E−02  2.703844E−02  3.158583E−02 A10  2.187680E−02  4.538243E−02  4.953674E−02 −2.824481E−04 3.003405E−02 −8.343036E−02  −3.180342E−02 A12 −1.784164E−02 −3.725517E−02 −4.076246E−02  4.645746E−02 1.589415E−02 1.076677E−01  1.614785E−02 A14  8.721997E−03  1.893600E−02  2.137993E−02 −4.076812E−02 −2.115701E−02  −8.009485E−02  −2.346857E−03 A16 −2.522490E−03 −5.740713E−03 −6.910572E−03  1.746261E−02 1.003246E−02 3.559523E−02 −1.740260E−03 A18  3.998321E−04  9.429409E−04  1.259935E−03 −3.869176E−03 −2.366168E−03  −8.733018E−03   9.249063E−04 A20 −2.694281E−05 −6.464225E−05 −1.010635E−04  3.502146E−04 2.269639E−04 9.115043E−04 −1.357825E−04 9th Surface 10th Surface 11th Surface 12th Surface 13th Surface 14th Surface 15th Surface k −3.957557E+00 0.000000E+00 −1.571851E+01 0.000000E+00  0.000000E+00 3.959969E+01 −1.693088E+01 A4 −3.158785E−02 1.963345E−02  3.988775E−02 3.434590E−03 −2.357801E−03 −6.107605E−02  −2.886477E−02 A6 −8.194884E−03 −3.150522E−02  −5.259404E−02 −3.110936E−02  −2.487374E−02 6.270318E−03 −4.673617E−04 A8  1.356408E−02 1.695016E−02  3.363259E−02 1.133533E−02  9.879249E−03 1.001963E−03  1.610504E−03 A10 −1.176001E−02 −5.242468E−03  −1.384286E−02 −2.116470E−03  −2.367206E−03 −3.046258E−04  −3.469929E−04 A12  6.810648E−03 2.150542E−04  3.637102E−03 1.575412E−04  3.798650E−04 3.378024E−05  3.720185E−05 A14 −2.639242E−03 3.734526E−04 −6.088672E−04 8.099374E−06 −4.078191E−05 −2.074009E−06  −2.316913E−06 A16  6.375402E−04 −1.201307E−04   6.312855E−05 −2.230875E−06   2.795510E−06 7.440853E−08  8.484617E−08 A18 −7.832807E−05 1.552373E−05 −3.708971E−06 1.416363E−07 −1.095971E−07 −1.465564E−09  −1.693454E−09 A20  3.128097E−06 −7.462384E−07   9.459338E−08 −3.070441E−09   1.853637E−09 1.227800E−11  1.420400E−11

The imaging lens in Example 2 achieves a ratio of a total track length to a diagonal length of an effective image area of the image sensor of 0.59, and a F number of 1.90. As shown in Table 9, the imaging lens in Example 2 satisfies the conditional expressions (1) to (20).

FIG. 4 shows spherical aberration (mm), astigmatism (mm), and distortion (%) of the imaging lens in Example 2. As shown in FIG. 4, each aberration is corrected excellently.

Example 3

The basic lens data is shown below in Table 3.

TABLE 3 Example 3 Unit mm f = 6.47 Fno = 1.70 ω(°) = 40.5 h = 5.61 TTL = 7.43 Surface Data i r d Nd νd (Object) Infinity Infinity  1 (Stop) Infinity −0.5520  2* 2.6736 0.6529 1.553 71.68 (νd1)  3* 4.8428 0.2296  4* 5.4672 0.7156 1.535 55.59 (νd2)  5* 56.5788 0.0402  6* 6.8484 0.3000 1.671 19.24 (νd3)  7* 4.2276 0.6326  8* Infinity 0.5126 1.661 20.37 (νd4)  9* Infinity 0.6528 10* −8.4122 0.6105 1.535 55.59 (νd5) 11* −3.5143 0.1435 12* 4.4313 0.4860 1.614 25.62 (νd6) 13* 3.9411 0.7647 14* −26.0352 0.5845 1.535 55.59 (νd7) 15* 3.6005 0.1735 16 Infinity 0.2100 1.517 64.20 17 Infinity 0.7895 Image Plane Infinity Constituent Lens Data TTL to diagonal length Lens Start Surface Focal Length of effective image area 1 2 9.742 0.66 2 4 11.261 3 6 −17.263 4 8 Infinity 5 10 10.816 6 12 −93.135 7 14 −5.874 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5th Surface 6th Surface 7th Surface 8th Surface k −1.064866E+00  0.000000E+00 0.000000E+00  0.000000E+00 0.000000E+00 0.000000E+00  0.000000E+00 A4  3.177453E−03 −6.350938E−03 −9.891558E−03  −5.743879E−02 −5.406567E−02  −1.034877E−02  −2.368019E−02 A6 −9.325935E−04 −4.018834E−03 1.926205E−02  7.956825E−02 7.148723E−02 9.187409E−03 −8.885643E−03 A8 −1.521028E−03  2.378061E−03 4.060642E−02 −6.976510E−02 4.855877E−02 2.218993E−03  1.305923E−02 A10  2.467780E−03  3.375852E−03 5.596666E−02  4.632589E−02 1.696030E−02 1.349520E−03 −1.159730E−02 A12 −1.934009E−03 −5.379121E−03 4.402623E−02 −2.356435E−02 1.017770E−03 −1.192261E−02   2.915091E−03 A14  8.037102E−04  3.555334E−03 2.128132E−02  8.701587E−03 4.381220E−03 1.435448E−02  3.471541E−03 A16 −1.811469E−04 −1.269062E−03 −6.249189E−03  −2.225857E−03 2.029735E−03 −8.118435E−03  −3.334395E−03 A18  1.912743E−05  2.323571E−04 1.016306E−03  3.584666E−04 −3.909224E−04  2.306159E−03  1.124157E−03 A20 −5.907360E−07 −1.702930E−05 −6.992156E−05  −2.709001E−05 2.667602E−05 −2.620992E−04  −1.379201E−04 9th Surface 10th Surface 11th Surface 12th Surface 13th Surface 14th Surface 15th Surface k  0.000000E+00 0.000000E+00 −1.689982E+01 0.000000E+00 0.000000E+00  3.313103E+01 −1.868933E+01 A4 −2.203363E−02 1.449963E−02  4.649595E−03 1.633705E−02 −6.959077E−03  −6.985511E−02 −3.931343E−02 A6  4.547433E−03 1.908000E−02  4.658101E−03 −4.194190E−02  −2.143442E−02   1.306365E−02  6.545264E−03 A8 −1.072816E−02 −3.188553E−02  −1.549450E−03 2.027248E−02 9.643361E−03 −5.242726E−04 −2.720452E−04 A10  9.506165E−03 2.154384E−02  2.655676E−03 −6.171249E−03  −2.584713E−03  −1.149334E−04 −5.502209E−05 A12 −5.185257E−03 −8.902867E−03  −1.361152E−03 1.211132E−03 4.433716E−04  1.918091E−05  8.965415E−06 A14  1.915470E−03 2.309152E−03  3.576085E−04 −1.546304E−04  4.800339E−05 −1.360464E−06 −6.015698E−07 A16 −4.804494E−04 −3.668693E−04  −5.152029E−05 1.263944E−05 3.160506E−06  5.274218E−08  2.146491E−08 A18  7.493294E−05 3.273873E−05  3.872288E−06 −6.034632E−07  −1.152366E−07  −1.089899E−09 −3.936503E−10 A20 −5.348708E−06 −1.255631E−06  −1.188026E−07 1.271644E−08 1.778649E−09  9.407000E−12  2.856200E−12

The imaging lens in Example 3 achieves a ratio of a total track length to a diagonal length of an effective image area of the image sensor of 0.66, and a F number of 1.70. As shown in Table 9, the imaging lens in Example 3 satisfies the conditional expressions (1) to (20).

FIG. 6 shows spherical aberration (mm), astigmatism (mm), and distortion (%) of the imaging lens in Example 3. As shown in FIG. 6, each aberration is corrected excellently.

Example 4

The basic lens data is shown below in Table 4.

TABLE 4 Example 4 Unit mm f = 6.43 Fno = 1.70 ω(°) = 40.7 h = 5.61 TTL = 7.43 Surface Data i r d Nd νd (Object) Infinity Infinity  1 Stop) Infinity −0.5140  2* 2.7153 0.5751 1.535 55.69 (νd1)  3* 4.4795 0.2330  4* 4.5067 0.8106 1.535 55.69 (νd2)  5* 985.1190 0.0400  6* 7.7938 0.3000 1.671 19.24 (νd3)  7* 4.1401 0.6852  8* Infinity 0.4971 1.671 19.24 (νd4)  9* Infinity 0.6667 10* −7.5095 0.5543 1.535 55.69 (νd5) 11* −3.1734 0.0500 12* 4.8797 0.4860 1.639 23.52 (νd6) 13* 4.2987 0.8224 14* −20.4368 0.5800 1.535 55.69 (νd7) 15* 3.6961 0.1987 16 Infinity 0.2100 1.517 64.20 17 Infinity 0.7898 Image Plane Infinity Constituent Lens Data TTL to diagonal length Lens Start Surface Focal Length of effective image area 1 2 11.577 0.66 2 4 8.463 3 6 −13.615 4 8 Infinity 5 10 9.838 6 12 −83.830 7 14 −5.804 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5th Surface 6th Surface 7th Surface 8th Surface k −1.165640E+00 0.000000E+00  0.000000E+00 0.000000E+00 0.000000E+00  0.000000E+00  0.000000E+00 A4  2.407155E−03 −6.357481E−03  −1.378605E−03 −5.506574E−02  −5.306401E−02  −9.422798E−04 −2.497255E−02 A6 −1.136477E−03 4.011549E−03 −5.543717E−03 6.725686E−02 6.682635E−02 −3.194636E−02 −4.406923E−03 A8 −1.400913E−03 2.097654E−03  5.121444E−03 4.651525E−02 −3.773416E−02   1.135593E−01 −7.290878E−03 A10  2.149422E−03 2.960161E−03  2.584968E−03 1.785383E−02 4.890427E−03 −1.733638E−01  2.837463E−02 A12 −1.642490E−03 4.561576E−03 −5.309641E−03 −1.668015E−03  8.762897E−03  1.583257E−01 −3.790681E−02 A14  6.629384E−04 2.931056E−03  3.664698E−03 −1.898092E−03  −7.559133E−03  −9.033514E−02  2.772153E−02 A16 −1.448906E−04 −1.014921E−03  −1.349400E−03 9.727347E−04 2.960091E−03  3.137068E−02 −1.175363E−02 A18  1.485026E−05 1.803399E−04  2.586612E−04 −1.936784E−04  −5.829856E−04  −6.032643E−03  2.705959E−03 A20 −4.451831E−07 −1.288123E−05  −2.034313E−05 1.424845E−05 4.617455E−05  4.917347E−04 −2.621535E−04 9th Surface 10th Surface 11th Surface 12th Surface 13th Surface 14th Surface 15th Surface k  0.000000E+00 0.000000E+00 −1.889059E+01 0.000000E+00  0.000000E+00 0.000000E+00 −1.171023E+01 A4 −2.209337E−02 2.383259E−02 −6.769979E−04 9.289485E−03 −2.086337E−02 4.811275E−02 −3.055569E−02 A6 −8.166155E−04 2.775992E−02  3.037625E−02 −2.579595E−02  −5.003623E−03 3.789250E−03  3.910336E−03 A8 −2.974296E−03 4.316987E−02 −3.351572E−02 9.878267E−03  1.750050E−03 1.049231E−03 −1.139673E−04 A10  2.297790E−03 2.650933E−02  1.749506E−02 −2.431639E−03  −3.261854E−04 −2.532936E−04  −2.968592E−05 A12 −3.276994E−04 −9.763200E−03  −5.510684E−03 4.028789E−04  4.619459E−05 2.548366E−05  4.074080E−06 A14 −2.504065E−04 2.238694E−03  1.074703E−03 4.408014E−05 −4.944985E−06 −1.454288E−06  −2.461236E−07 A16  1.173308E−04 −3.129285E−04  −1.257928E−04 3.083933E−06  3.572006E−07 4.890995E−08  8.176797E−09 A18 −1.741597E−05 2.452936E−05  8.066001E−06 −1.255318E−07  −1.474916E−08 −9.053312E−10  −1.444917E−10 A20  7.216289E−07 −8.283324E−07  −2.172977E−07 2.252216E−09  2.559556E−10 7.126300E−12  1.064500E−12

The imaging lens in Example 4 achieves a ratio of a total track length to a diagonal length of an effective image area of the image sensor of 0.66, and a F number of 1.70. As shown in Table 9, the imaging lens in Example 4 satisfies the conditional expressions (1) to (20).

FIG. 8 shows spherical aberration (mm), astigmatism (mm), and distortion (%) of the imaging lens in Example 4. As shown in FIG. 8, each aberration is corrected excellently.

Example 5

The basic lens data is shown below in Table 5.

TABLE 5 Example 5 Unit mm f = 6.48 Fno = 1.70 ω(°) = 40.4 h = 5.61 TTL = 7.43 Surface Data i r d Nd νd (Object) Infinity Infinity  1 (Stop) Infinity −0.5400  2* 2.6585 0.5987 1.553 71.68 (νd1)  3* 4.4537 0.2297  4* 4.8054 0.7707 1.553 71.68 (νd2)  5* 59.8622 0.0400  6* 6.4490 0.3000 1.821 24.06 (νd3)  7* 4.1064 0.6580  8* Infinity 0.5327 1.614 25.59 (νd4)  9* Infinity 0.5965 10* −7.7954 0.6274 1.535 55.69 (νd5) 11* −3.0557 0.0622 12* 4.6048 0.4900 1.639 23.52 (νd6) 13* 3.9018 0.6005 14* −22.0265 0.6250 1.535 55.69 (νd7) 15* 3.6383 0.1677 16 Infinity 0.2100 1.517 64.20 17 Infinity 0.9897 Image Plane Infinity Constituent Lens Data TTL to diagonal length Lens Start Surface Focal Length of effective image area 1 2 10.654 0.66 2 4 9.396 3 6 −14.611 4 8 Infinity 5 10 8.983 6 12 −54.916 7 14 −5.789 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5th Surface 6th Surface 7th Surface 8th Surface k −1.123615E+00  0.000000E+00  0.000000E+00  0.000000E+00  0.000000E+00  0.000000E+00  0.000000E+00 A4  2.826094E−03 −6.215953E−03 −7.058497E−03 −4.981478E−02  4.087821E−02 −8.769202E−03 −2.220944E−02 A6 −1.034354E−03 −4.227638E−03  1.743212E−02  6.286350E−02  4.444131E−02  8.944080E−03 −1.683104E−02 A8 −1.537707E−03  2.364984E−03 −3.978824E−02 −5.053544E−02 −2.003250E−02 −1.261936E−02  2.488195E−02 A10  2.459413E−03  3.384690E−03  5.572519E−02  3.054674E−02 −1.026260E−03  4.262744E−02 −1.875975E−02 A12 −1.934148E−03 −5.376962E−03 −4.407637E−02 −1.505856E−02  6.105949E−03 −6.676956E−02  1.434926E−03 A14  8.043945E−04  3.555550E−03  2.129224E−02  5.925411E−03 −3.355662E−03  5.576277E−02  8.186158E−03 A16 −1.811469E−04 −1.269123E−03 −6.215654E−03 −1.711730E−03  8.182697E−04 −2.622952E−02 −6.175752E−03 A18  1.912743E−05  2.323367E−04  1.001587E−03  3.101485E−04 −5.859747E−05  6.593415E−03  1.896653E−03 A20 −5.907360E−07 −1.703129E−05 −6.816062E−05 −2.533842E−05 −5.043878E−06 −6.879189E−04 −2.201866E−04 9th Surface 10th Surface 11th Surface 12th Surface 13th Surface 14th Surface 15th Surface k 0.000000E+00 0.000000E+00 −1.803262E+01 0.000000E+00  0.000000E+00  2.053562E+01 −1.867662E+01 A4 −2.055796E−02  2.062833E−02 −1.477596E−02 4.463007E−03 −3.948271E−02 −9.137785E−02 −4.917645E−02 A6 −5.158220E−03  9.828700E−03  2.317586E−03 −3.946914E−02  −5.804294E−03  2.613740E−02  1.408851E−02 A8 4.339511E−03 −2.154628E−02   1.112499E−03 2.403704E−02  4.259111E−03 −3.782369E−03 −2.284716E−03 A10 4.112174E−03 1.445803E−02 −9.909718E−04 −9.040455E−03  −1.335646E−03  3.510151E−04  2.281035E−04 A12 2.826636E−03 −5.899703E−03   2.984228E−04 2.135529E−03  2.596764E−04 −2.279565E−05 −1.455474E−05 A14 −8.152038E−04  1.529932E−03 −4.149504E−05 −3.146054E−04  −3.139089E−05  1.074683E−06  5.815854E−07 A16 5.616445E−05 −2.478921E−04   2.094439E−06 2.828063E−05  2.290347E−06 −3.590445E−08 −1.332108E−08 A18 2.223853E−05 2.305538E−05  5.879563E−08 −1.423294E−06  −9.217768E−08  7.572053E−10  1.383620E−10 A20 −3.617679E−06  −9.379146E−07  −6.543553E−09 3.071153E−08  1.563726E−09 −7.421800E−12 −1.852000E−13

The imaging lens in Example 5 achieves a ratio of a total track length to a diagonal length of an effective image area of the image sensor of 0.66, and a F number of 1.70. As shown in Table 9, the imaging lens in Example 5 satisfies the conditional expressions (1) to (20).

FIG. 10 shows spherical aberration (mm), astigmatism (mm), and distortion (%) of the imaging lens in Example 5. As shown in FIG. 10, each aberration is corrected excellently.

Example 6

The basic lens data is shown below in Table 6.

TABLE 6 Example 6 Unit mm f = 6.73 Fno = 1.90 ω(°) = 42.6 h = 6.25 TTL = 7.43 Surface Data i r d Nd νd (Object) Infinity Infinity  1 (Stop) Infinity −0.4100  2* 2.6191 0.5756 1.569 71.31 (νd1)  3* 4.8176 0.2136  4* 5.8469 0.6729 1.593 68.35 (νd2)  5* 27.2772 0.0400  6* 15.2172 0.3045 1.614 25.59 (νd3)  7* 6.7351 0.4984  8* Infinity 0.4893 1.614 25.59 (νd4)  9* Infinity 0.6884 10* 20.3819 0.5200 1.535 55.69 (νd5) 11* −102.2700 0.5702 12* 4.3537 0.5000 1.614 25.59 (νd6) 13* 4.1678 0.5634 14* 31.1786 0.7123 1.535 55.69 (νd7) 15* 3.4887 0.1846 16 Infinity 0.2100 1.517 64.20 17 Infinity 0.7565 Image Plane Infinity Constituent Lens Data TTL to diagonal length Lens Start Surface Focal Length of effective image area 1 2 9.211 0.59 2 4 12.409 3 6 −19.945 4 8 Infinity 5 10 31.824 6 12 6844.487 7 14 −7.411 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5th Surface 6th Surface 7th Surface 8th Surface k −1.867615E+00  0.000000E+00  6.944937E+00 0.000000E+00 0.000000E+00  0.000000E+00  0.000000E+00 A4  2.498889E−03 −9.906157E−03 −1.329954E−02 −8.048824E−02  −8.103177E−02  −3.703416E−03 −2.468413E−02 A6  1.119270E−02 −4.668607E−03  2.272595E−02 6.572381E−02 6.734047E−02 −1.889357E−02 −5.520646E−02 A8 −2.901131E−02  2.425466E−03 −4.339859E−02 4.316187E−02 7.881047E−02  1.473487E−01  1.501458E−01 A10  3.413533E−02  3.691365E−03  6.314402E−02 −1.536769E−01  −2.236522E−01  −3.005743E−01 −2.287034E−01 A12 −2.493974E−02 −6.109858E−03 −5.386591E−02 1.714527E−01 2.346696E−01  3.460899E−01  2.151267E−01 A14  1.123950E−02  4.126790E−03  2.868657E−02 −1.089054E−01  −1.421832E−01  −2.457184E−01 −1.265224E−01 A16 −3.068087E−03 −1.507003E−03 −9.431656E−03 4.147594E−02 5.213302E−02  1.063766E−01  4.496540E−02 A18  4.658980E−04  2.822407E−04  1.759405E−03 −8.729787E−03  −1.068201E−02  −2.567988E−02 −8.771997E−03 A20 −3.025450E−05 −2.118824E−05 −1.438788E−04 7.725577E−04 9.321978E−04  2.649627E−03  7.143504E−04 9th Surface 10th Surface 11th Surface 12th Surface 13th Surface 14th Surface 15th Surface k  0.000000E+00 0.000000E+00 −1.645385E+01  0.000000E+00  0.000000E+00  3.894788E+01 −1.668924E+01  A4 −3.416899E−02 2.282875E−03  1.034702E−02 −2.154504E−02 −2.921975E−02 −8.495061E−02 −3.824491E−02  A6  3.839629E−03 −1.097630E−02  −1.517155E−02 −7.047830E−03 −1.777010E−03  2.502196E−02 8.378515E−03 A8 −2.776179E−03 2.149419E−03  7.991279E−03  1.984519E−03  6.908232E−04 −4.329178E−03 −8.799438E−04  A10  1.647994E−03 2.007544E−04 −3.434532E−03 −2.792581E−04 −1.255530E−04  4.838605E−04 3.055358E−05 A12 −2.121671E−04 −5.304199E−04   1.014016E−03 −1.883657E−05  1.556764E−05 −3.543360E−05 2.467202E−06 A14 −2.187335E−04 2.333012E−04 −2.004302E−04  1.378006E−05 −9.612953E−07  1.689195E−06 −3.280899E−07  A16  9.887970E−05 −5.448905E−05   2.549361E−05 −1.934510E−06  1.484111E−08 −5.057326E−08 1.570750E−08 A18 −1.016927E−05 7.000486E−06 −1.860626E−06  1.143780E−07  9.500777E−10  8.649810E−10 −3598855E−10  A20 −4.724753E−07 −3.732594E−07   5.830827E−08 −2.507328E−09 −3.232710E−11 −6.458000E−12 3.273700E−12

The imaging lens in Example 6 achieves a ratio of a total track length to a diagonal length of an effective image area of the image sensor of 0.59, and a F number of 1.90. As shown in Table 9, the imaging lens in Example 6 satisfies the conditional expressions (1) to (20).

FIG. 12 shows spherical aberration (mm), astigmatism (mm), and distortion (%) of the imaging lens in Example 6. As shown in FIG. 12, each aberration is corrected excellently.

Example 7

The basic lens data is shown below in Table 7.

TABLE 7 Example 7 Unit mm f = 6.68 Fno = 1.95 ω(° ) = 42.9 h = 6.25 TTL = 7.42 Surface Data i r d Nd νd (Object) Infinity Infinity  1 (Stop) Infinity −0.4400  2* 2.6134 0.5295 1.535 55.69 (νd1)  3* 4.4201 0.1856  4* 4.1215 0.6698 1.535 55.69 (νd2)  5* 21.9503 0.0382  6* 15.6932 0.2867 1.671 19.24 (νd3)  7* 5.7261 0.4465  8* 60.0000 0.5139 1.535 55.69 (νd4)  9* 100.0000 0.6419 10* 19.1843 0.5530 1.535 55.69 (νd5) 11* −64.9320 0.5020 12* 3.8059 0.5471 1.671 19.24 (νd6) 13* 3.7684 0.7479 14* 36.6048 0.6866 1.535 55.69 (νd7) 15* 3.5099 0.4500 16 Infinity 0.2100 1.517 64.20 17 Infinity 0.4791 Image Plane Infinity Constituent Lens Data TTL to diagonal length Lens Start Surface Focal Length of effective image area 1 2 10.847 0.59 2 4 9.365 3 6 −13.598 4 8 279.223 5 10 27.754 6 12 117.428 7 14 −7.312 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5th Surface 6th Surface 7th Surface 8th Surface k −1.789627E+00 −1.766900E+01 −1.293193E+00 0.000000E+00  0.000000E+00  8.279186E+00  0.000000E+00 A4 −1.480424E−02  3.087080E−03 −3.350424E−02 −8.365533E−02  −5.727236E−02 −2.719050E−02 −1.255138E−02 A6  6.306532E−02  8.644056E−03  9.090208E−02 1.174319E−01  8.972264E−02  1.000457E−01 −9.333634E−02 A8 −1.194037E−01 −3.038763E−02 −1.881442E−01 −9.734682E−02  −3.496004E−02 −1.711987E−01  2.235122E−01 A10  1.325184E−01  4.432886E−02  2.509239E−01 2.647376E−02 −5.726641E−02  1.901211E−01 −3.150691E−01 A12 −9.226313E−02 −3.686273E−02 −2.086365E−01 2.988643E−02  9.638592E−02 −1.327258E−01  2.791362E−01 A14  4.028450E−02  1.861244E−02  1.096956E−01 −3.618042E−02  −6.913408E−02  5.368836E−02 −1.563712E−01 A16 −1.069353E−02 −5.518094E−03 −3.539098E−02 1.759085E−02  2.783672E−02 −1.000862E−02  5.356455E−02 A18  1.576807E−03  8.719527E−04  6.408401E−03 −4.208652E−03  −6.098719E−03 −7.199337E−05 −1.018542E−02 A20 −9.921192E−05 −5.668721E−05 −5.012949E−04 4.006576E−04  5.634069E−04  2.087462E−04  8.182976E−04 9th Surface 10th Surface 11th Surface 12th Surface 13th Surface 14th Surface 15th Surface k  0.000000E+00 0.000000E+00 0.000000E+00  0.000000E+00  0.000000E+00  0.000000E+00 −1.429443E+01 A4 −3.111909E−02 2.281904E−02 2.387145E−02 −1.121921E−02 −1.359952E−02 −7.440283E−02 −3.319697E−02 A6 −9.280201E−03 −4.377798E−02  −3.768255E−02  −1.927580E−02 −1.581091E−02  1.311778E−02  2.044940E−03 A8  2.382167E−02 3.638632E−02 2.726798E−02  7.417641E−03  6.639393E−03 −8.714924E−04  8.990087E−04 A10 −3.267262E−02 −2.032860E−02  −1.219695E−02  −1.438671E−03 −1.616178E−03 −1.079272E−05 −2.235562E−04 A12  2.725750E−02 7.046741E−03 3.328119E−03  1.143120E−04  2.546767E−04  5.910504E−06  2.393066E−05 A14 −1.379099E−02 −1.517491E−03  −5.557176E−04   3.415916E−06 −2.590541E−05 −4.403856E−07 −1.440038E−06 A16  4.127688E−03 1.976034E−04 5.563538E−05 −1.167047E−06  1.625391E−06  1.636313E−08  5.040712E−08 A18 −6.631214E−04 −1.418998E−05  −3.076089E−06   6.814305E−08 −5.655775E−08 −3.175534E−10 −9.588362E−10 A20  4.369121E−05 4.301586E−07 7.236326E−08 −1.251775E−09  8.251340E−10  2.571596E−12  7.667720E−12

The imaging lens in Example 7 achieves a ratio of a total track length to a diagonal length of an effective image area of the image sensor of 0.59, and a F number of 1.95. As shown in Table 9, the imaging lens in Example 7 satisfies the conditional expressions (1) to (6), and (8) to (20).

FIG. 14 shows spherical aberration (mm), astigmatism (mm), and distortion (%) of the imaging lens in Example 7. As shown in FIG. 14, each aberration is corrected excellently.

Example 8

The basic lens data is shown below in Table 8.

TABLE 8 Example 8 Unit mm f = 6.78 Fno = 1.95 ω(°) = 42.5 h = 6.25 TTL = 7.46 Surface Data i r d Nd νd (Object) Infinity Infinity  1 (Stop) Infinity −0.4400  2* 2.6031 0.5415 1.535 55.69 (νd1)  3* 4.4442 0.2006  4* 4.2538 0.6961 1.535 55.69 (νd2)  5* 24.7720 0.0524  6* 15.0911 0.2988 1.671 19.24 (νd3)  7* 5.7244 0.4912  8* 150.0000 0.4239 1.671 19.24 (νd4)  9* 100.0000 0.6503 10* 18.1471 0.5267 1.535 55.69 (νd5) 11* −66.0832 0.5490 12* 3.8255 0.5492 1.671 19.24 (νd6) 13* 3.7658 0.7210 14* 36.5003 0.6872 1.535 55.69 (νd7) 15* 3.4226 0.4500 16 Infinity 0.2100 1.517 64.20 17 Infinity 0.4833 Image Plane Infinity Constituent Lens Data TTL to diagonal length Lens Start Surface Focal Length of effective image area 1 2 10.657 0.60 2 4 9.491 3 6 −13.929 4 8 −448.791 5 10 26.679 6 12 133.572 7 14 −7.113 Aspheric Surface Data 2nd Surface 3rd Surface 4th Surface 5th Surface 6th Surface 7th Surface 8th Surface k −1.785555E+00 −1.754548E+01 −1.365698E+00 0.000000E+00  0.000000E+00  8.197440E+00  0.000000E+00 A4 −1.477312E−02  2.975338E−03 −3.350378E−02 −8.318380E−02  −5.758537E−02 −2.726326E−02 −1.280290E−02 A6  6.310370E−02  8.613362E−03  9.090652E−02 1.174541E−01  8.969063E−02  1.001036E−01 −9.347525E−02 A8 −1.193980E−01 −3.039087E−02 −1.881477E−01 −9.734030E−02  −3.497165E−02 −1.711812E−01  2.234862E−01 A10  1.325190E−01  4.432896E−02  2.509223E−01 2.647463E−02 −5.726996E−02  1.901276E−01 −3.150695E−01 A12 −9.226315E−02 −3.686254E−02 −2.086369E−01 2.988614E−02  9.638503E−02 −1.327229E−01  2.791393E−01 A14  4.028445E−02  1.861251E−02  1.096955E−01 −3.618076E−02  −6.913420E−02  5.368984E−02 −1.563688E−01 A16 −1.069355E−02 −5.518079E−03 −3.539096E−02 1.759065E−02  2.783677E−02 −1.000773E−02  5.356594E−02 A18  1.576798E−03  8.719519E−04  6.408420E−03 −4.208754E−03  −6.098659E−03 −7.140641E−05 −1.018471E−02 A20 −9.921431E−05 −5.668911E−05 −5.012843E−04 4.006141E−04  5.634462E−04  2.090848E−04  8.186439E−04 9th Surface 10th Surface 11th Surface 12th Surface 13th Surface 14th Surface 15th Surface k  0.000000E+00 4.729962E+01 8.732535E+01  0.000000E+00  0.000000E+00  4.432099E+01 −1.628168E+01 A4 −3.124508E−02 2.281568E−02 2.370163E−02 −1.133923E−02 −1.354573E−02 −7.438362E−02 −3.319915E−02 A6 −9.167124E−03 4.380777E−02 −3.768592E−02  −1.927824E−02 −1.580575E−02  1.311701E−02  2.049367E−03 A8  2.382962E−02 3.638761E−02 2.726783E−02  7.417671E−03  6.639490E−03 −8.715081E−04  8.990471E−04 A10 −3.267528E−02 −2.032862E−02  −1.219694E−02  −1.438673E−03 −1.616179E−03 −1.079261E−05 −2.235567E−04 A12  2.725587E−02 7.046718E−03 3.328122E−03  1.143134E−04  2.546766E−04  5.910517E−06  2.393066E−05 A14 −1.379165E−02 −1.517495E−03  −5.557174E−04   3.415916E−06 −2.590541E−05 −4.403856E−07 −1.440038E−06 A16  4.127454E−03 1.976034E−04 5.563538E−05 −1.167047E−06  1.625391E−06  1.636313E−08  5.040712E−08 A18 −6.631994E−04 −1.419008E−05  −3.076089E−06   6.814305E−08 −5.655775E−08 −3.175587E−10 −9.588373E−10 A20  4.366513E−05 4.301586E−07 7.236326E−08 −1.251775E−09  8.251340E−10  2.571453E−12  7.667720E−12

The imaging lens in Example 8 achieves a ratio of a total track length to a diagonal length of an effective image area of the image sensor of 0.60, and a F number of 1.95. As shown in Table 9, the imaging lens in Example 8 satisfies the conditional expressions (1) to (20).

FIG. 16 shows spherical aberration (mm), astigmatism (mm), and distortion (%) of the imaging lens in Example 8. As shown in FIG. 16, each aberration is corrected excellently.

In table 9, values of conditional expressions (1) to (20) related to Examples 1 to 8 are shown.

TABLE 9 Conditional Expressions Example 1 Example 2 Example 3 Example 4  (1) | r 13/r 14 | 10.28 21.57 7.23 5.53  (2) νd 6 19.24 25.59 25.62 23.52  (3) f 2/f 7 −1.30 −2.20 −1.92 −1.46  (4) f 1/| f 6 | 0.076 0.050 0.105 0.138  (5) r 12/| r 13 | 0.11 0.05 0.15 0.21  (6) D 4/T 4 0.64 0.64 0.79 0.75  (7) νd 4 19.24 23.52 20.37 19.24  (6) T 2/T 4 0.08 0.06 0.06 0.06  (9) f 1/f 1.59 1.24 1.51 1.80 (10) | f 6 |/f 20.98 24.98 14.39 13.03 (11) f 3/f 7 1.92 2.90 2.94 2.35 (12) r 4/f 3.72 5.67 8.74 153.16 (13) r 11/f 0.57 0.58 0.68 0.76 (14) r 12/f 0.56 0.58 0.61 0.67 (15) | r 13 |/f 5.33 12.28 4.02 3.18 (16) r 2/T 1 22.49 24.86 21.09 19.22 (17) r 3/T 1 21.43 32.09 23.81 19.34 (18) | r 9 |/T 4 28.24 20.70 12.89 11.26 (19) r 12/T 6 5.21 5.40 5.15 5.23 (20) | r 13 |/D 7 51.74 109.75 44.54 35.24 Conditional Expressions Example 5 Example 6 Example 7 Example 8  (1) | r 13/r 14 | 6.05 8.94 10.43 10.66  (2) νd 6 23.52 25.59 19.24 19.24  (3) f 2/f 7 −1.62 −1.67 −1.28 −1.33  (4) f 1/| f 6 | 0.194 0.001 0.092 0.080  (5) r 12/| r 13 | 0.18 0.13 0.10 0.10  (6) D 4/T 4 0.89 0.71 0.80 0.65  (7) νd 4 25.59 25.59 55.69 19.24  (8) T 2/T 4 0.07 0.06 0.06 0.08  (9) f 1/f 1.65 1.37 1.62 1.57 (10) | f 6 |/f 8.48 1017.05 17.59 19.70 (11) f 3/f 7 2.52 2.69 1.86 1.96 (12) r 4/f 9.25 4.05 3.29 3.65 (13) r 11/f 0.71 0.65 0.57 0.56 (14) r 12/f 0.60 0.62 0.56 0.56 (15) | r 13 |/f 3.40 4.63 5.48 5.38 (16) r 2/T 1 19.39 22.55 23.82 22.16 (17) r 3/T 1 20.92 27.37 22.21 21.21 (18) | r 9 |/T 4 13.07 29.61 29.88 27.91 (19) r 12/T 6 6.50 7.40 5.04 5.22 (20) | r 13 |/D 7 35.24 43.77 53.31 53.11

When the imaging lens according to the present invention is adopted to a product with the camera function, there is realized contribution to the low profile and the low F-number of the camera and also high performance thereof.

DESCRIPTION OF REFERENCE NUMERALS

-   ST: aperture stop -   L1: first lens -   L2: second lens -   L3: third lens -   L4: fourth lens -   L5: fifth lens -   L6: sixth lens -   L7: seventh lens -   IR: filter -   IMG: imaging plane 

What is claimed is:
 1. An imaging lens comprising, in order from an object side to an image side, a first lens with positive refractive power, a second lens with positive refractive power, a third lens with negative refractive power, a fourth lens, a fifth lens with positive refractive power, a sixth lens with positive or negative refractive power, and a seventh lens with negative refractive power, wherein said first lens is formed in a meniscus shape having an object-side surface being convex in a paraxial region, said second lens has an image-side surface being concave in a paraxial region, said sixth lens has an image-side surface being concave in a paraxial region, and said seventh lens has an image-side surface being concave in a paraxial region, and the following conditional expression (1) is satisfied: 3.85<|r13/r14|  (1) where r13: a paraxial curvature radius of an object-side surface of the seventh lens, and r14: a paraxial curvature radius of the image-side surface of the seventh lens.
 2. The imaging lens according to claim 1, wherein an object-side surface of said third lens is convex in a paraxial region.
 3. The imaging lens according to claim 1, wherein the following conditional expression (2) is satisfied: 13.00<vd6<34.00  (2) where vd6: an abbe number at d-ray of the sixth lens.
 4. The imaging lens according to claim 1, wherein the following conditional expression (3) is satisfied: −3.50<f2/f7<−0.50  (3) where f2: a focal length of the second lens, and f7: a focal length of the seventh lens.
 5. The imaging lens according to claim 1, wherein the following conditional expression (4) is satisfied: 0.00<f1/|f6|<0.30  (4) where f1: a focal length of the first lens, and f6: a focal length of the sixth lens.
 6. The imaging lens according to claim 1, wherein the following conditional expression (5) is satisfied: 0.02<r12/|r13|<0.35  (5) where r12: a paraxial curvature radius of an image-side surface of the sixth lens, and r13: a paraxial curvature radius of an object-side surface of the seventh lens.
 7. The imaging lens according to claim 1, wherein the following conditional expression (6) is satisfied: 0.15<D4/T4<1.05  (6) where D4: a thickness along an optical axis of the fourth lens, and T4: a distance along an optical axis from an image-side surface of the fourth lens to an object-side surface of the fifth lens. 